Method for catalyst purge control based on engine temperature and vehicle using the same

Abstract

A method for catalyst purge control may include the steps of: performing, by a catalyst purge electronic control unit (ECU), catalyst purge control based on engine temperature; calculating an estimated engine temperature the catalyst purge ECU when fuel-cut is completed, and controlling, by the catalyst purge ECU, an amount of purge fuel injected by an injector based on the estimated engine temperature for the catalyst purge control.

What is claimed is: 
     
       1. A method for catalyst purge control, comprising the steps of:
 performing, by a catalyst purge electronic control unit (ECU), catalyst purge control based on engine temperature; 
 calculating an estimated engine temperature by the catalyst purge ECU when fuel-cut is completed; and 
 controlling, by the catalyst purge ECU, an amount of purge fuel injected by an injector based on the estimated engine temperature for the catalyst purge control, 
 wherein performing the catalyst purge control comprises:
 receiving a temperature value detected by a temperature sensor when a fuel-cut ON signal is changed to a fuel-cut OFF signal; 
 calculating the estimated engine temperature when the detected temperature value is received; 
 controlling an injection amount of catalyst purge fuel based on an operating condition determined by the calculation of the estimated engine temperature; and 
 controlling an injection amount of rich fuel based on the operating condition, and outputting a fuel injection signal to control the amount of the purge fuel. 
 
 
     
     
       2. The method of  claim 1 , wherein the estimated engine temperature is calculated by a temperature modeling. 
     
     
       3. The method of  claim 2 , wherein the temperature sensor is a coolant temperature sensor or an engine oil sensor, and the temperature modeling is based on a temperature detection value of the coolant temperature sensor. 
     
     
       4. The method of  claim 1 , wherein receiving the temperature value comprises:
 checking the fuel-cut ON signal; 
 obtaining the detected temperature value by detecting vehicle information at a time of fuel-cut ON; and 
 checking the fuel-cut OFF signal when the detected temperature value is obtained. 
 
     
     
       5. The method of  claim 4 , wherein the temperature value includes at least one of a coolant temperature value or an oil temperature value. 
     
     
       6. The method of  claim 1 , wherein calculating the estimated engine temperature comprises:
 calculating the estimated engine temperature by a temperature modeling based on the detected temperature value. 
 
     
     
       7. The method of  claim 6 , wherein the temperature modeling is performed when the detected temperature value is a coolant temperature value. 
     
     
       8. The method of  claim 1 , wherein controlling the injection amount of catalyst purge fuel comprises:
 determining the operating condition by setting the estimated engine temperature as a threshold; 
 dividing the operating condition into a low-temperature operating condition and a high-temperature operating condition based on the estimated engine temperature; 
 reducing the injection amount of rich fuel in the low-temperature operating condition and using the injection amount of rich fuel in the high-temperature operating condition; and 
 outputting a fuel injection signal to control the injection amount of rich fuel. 
 
     
     
       9. The method of  claim 8 , wherein the operating condition is the low-temperature operating condition when the estimated engine temperature is less than a threshold value, and the operating condition is the high-temperature operating condition when the estimated engine temperature is equal to or greater than the threshold value. 
     
     
       10. The method of  claim 9 , wherein the threshold value is a temperature at which a generation of nitrogen oxide is reduced in an engine. 
     
     
       11. The method of  claim 8 , wherein the injection amount of rich fuel means a state in which an injection amount of fuel is richer than a theoretical air-fuel ratio (λ=1) for catalyst purge. 
     
     
       12. The method of  claim 8 , wherein the outputting the fuel injection signal to control the amount of purge fuel is performed by variable purge time-based fuel rate control using a purge time change when a purge fuel rate lambda value is maintained. 
     
     
       13. The method of  claim 8 , wherein the outputting the fuel injection signal to control the amount of purge fuel is performed by variable purge fuel rate control using a purge fuel rate change when a purge time is maintained. 
     
     
       14. The method of  claim 1 , wherein when the estimated engine temperature is not calculated, the catalyst purge ECU changes to catalyst purge control based on deterioration using catalyst deterioration. 
     
     
       15. A vehicle comprising:
 a catalyst purge electronic control unit (ECU) configured to:
 receive a temperature value detected by a temperature sensor when a fuel-cut ON signal is changed to a fuel-cut OFF signal, 
 calculate an estimated engine temperature when the detected temperature value is received, 
 control an injector configured to inject an amount of purge fuel to a catalyst by catalyst purge control based on an operating condition determined by the estimated engine temperature, when the estimated engine temperature is calculated, 
 control an injection amount of rich fuel based on the operating condition, and output a fuel injection signal to control the amount of the purge fuel, and 
 control the amount of the purge fuel injected by the injector by the catalyst purge control based on deterioration of the catalyst, when the estimated engine temperature is not calculated. 
 
 
     
     
       16. The vehicle of  claim 15 , wherein the catalyst purge ECU comprises an engine-based purge map for calculating a value of the estimated engine temperature, and a purge fuel control map for calculating a control value of the amount of the purge fuel. 
     
     
       17. The vehicle of  claim 16 , wherein the engine- based purge map comprises a temperature sensor purge map for calculating the estimated engine temperature value via a temperature sensor, and a temperature modeling purge map for calculating the estimated engine temperature value via a temperature modeling. 
     
     
       18. The vehicle of  claim 16 , wherein the purge fuel control map comprises a variable purge time map for controlling the amount of the purge fuel by variable purge time-based fuel rate control using a purge time change when a purge fuel rate lambda value is maintained, and a variable purge fuel map for controlling the amount of the purge fuel by variable purge fuel rate control using a purge fuel rate change when a purge time is maintained.